Oxidized Bitumen or Blown Asphalt or Blown Bitumen is produced by either Continuous or Staggered Blowing Process. Heated Penetration Grade Bitumen under controlled environment is blown with air which controls the oil content in the Bitumen while it oxidized. The different grades for suited applications produced are designated by two numbers to indicate the mid–points of their softening point and penetration ranges.
This process gives the bitumen more rubbery properties than its original formula and they are simply harder bitumen. Hard bitumen under controlled temperature conditions is widely used as an anti–slip layer compound in the piling industry, for the manufacture of roofing felts, the roofing and waterproofing industries, for sound dampening felts and under carriage sealant in the automotive industry, electric cable joint protection, joint filling compound, sealant compound and many others. Also used in sealing saw cuts and joints where expected movements are minimum. It is also used in the manufacturing of bituminous marine mastic for the oil & gas pipeline joints.
Oxidized Bitumen or Blown Asphalt is produced by blowing hot air into the penetration bitumen. This action makes the bitumen more rubbery than its original formula and it becomes harder bitumen. This bitumen recovery the weight loss under heating. Due to low thermal sensitivity, the softening point is much higher than regular bitumen and the penetration index (PI) is higher than road construction bitumen (8>PI>2) due to the letter has a gel–like structure because of asphalt accumulation. Special physical properties of its grade can be used in different applications in the construction business. Oxidized Bitumen is made by ongoing or Staggered Blowing Process. Heated Penetration bitumen under controlled environment is blown with air which controls oil content in bitumen while it oxidized.
Blown Bitumen is produced by the air blowing of penetration grade bitumen. This is done at high temperatures, resulting in a material of a much higher penetration index. Blown Bitumen is based on petroleum bitumen which is made by blowing bitumen 60/70 by very hot air. The designation of the Blown Bitumen refers to the midpoint of the softening point acceptance criteria. It is based on petroleum bitumen which is made by blowing bitumen 60/70 by very hot air. In addition, the numbers relate to the midpoint of the material’s softening point and penetration respectively. The softening point value measured by Ring and Ball method as determined by ASTM D36. Also, the penetration value is in 1/10 mm as determined by IP49 or ASTM–D5.
Oxidized Bitumen is a solid or semi–black solid material and gradually liquid when heated. Oxidized Bitumen grades are blown or oxidized Asphalt ‘s which are produced by passing air through soft bitumen under controlled temperature conditions. This process gives the bitumen more rubbery properties than penetration or hard grade bitumen and a variety of uses in industrial applications.
Oxidized Bitumen is Blown Asphalt which is exporting in various grades as Oxidized Bitumen 115/15, Blown Bitumen 90/40, 75/25, 85/25, 90/15, 105/35, 150/5, 95/25 and any other grade will produce according to order. Throughout the world, more than 7 types of bitumen that is produced depend on the type of weather conditions one of them is Oxidized Bitumen or Blown Bitumen, Oxidized Bitumen grades are suitable for sealing saw cuts and joints where there is expected to be the minimum amount of moving in the joint. Their wide temperature range prevents bleeding in high–temperature applications.
Some of the major advantages of Oxidized Bitumen are that it is completely water resistant, highly flexible and durable. Further, it is chemically very stable. Oxidized bitumen is a very flexible compound that is not only chemically stable but also a very durable compound apart from being completely water resistant. Lastly, it has some very prominent technical advantages that makes it a very sought after compound in various applications.
Oxidized Bitumen Grades are suitable for sealing saw cuts and joints where there is expected to be the minimum amount of moving in the joint. Their wide temperature range prevents bleeding in high–temperature applications. Oxidized bitumen can also be used in industrial applications like Roofing, Flooring, Mastics, Pipe coatings, Electrical applications to name a few.
Oxidized Bitumen or Oxidized Asphalt range is used in the waterproofing industries, for carpet–backing, corrosion protection, acoustic panels and the manufacture of paints, amongst other applications.
Air–Blowing: The manufacturing process used to make oxidized roofing asphalts in which air is blown through an asphalt flux. An exothermic oxidation reaction occurs, yielding an asphalt that is harder, more viscous, less volatile, and less temperature–susceptible than the asphalt flux used as the feedstock to the process.
Asphalt, Oxidized (Blown Or Air–Refined): Asphalt treated by blowing air through it at elevated temperatures to produce physical properties required for the industrial use of the final product. Oxidized asphalts are used in roofing operations, pipe coating, under sealing for Portland cement concrete pavements, hydraulic applications, membrane envelopes, some paving–grade mixes and the manufacture of paints.
Blowing Still: A closed process vessel fitted at its base with a sparger and used in the air–blowing process to make many types of roofing asphalt.
Coating Asphalt: An air blown or oxidized asphalt used to manufacture roofing materials used in a variety of roofing systems such as asphalt shingles, polymer–modified bitumen roofing, reinforcing and underlayment felts, and roll roofing products.
Modified Bitumen: A roofing system based on membranes manufactured by impregnating or coating one or more fabric plies with a straight run or oxidized asphalt modified using a polymer, usually atactic polypropylene (APP) or styrene–butadiene–styrene (SBS). Modified bitumen systems may be torch–applied or installed by adhesion in hot asphalt or a cold–applied, solvent–based asphalt adhesive (cutback asphalt). Modified bitumen systems are used on low–slope (primarily commercial or industrial) roofs.
Oxidized Bitumen Advantages
Some of the major advantages of oxidized bitumen are that it is completely water resistant, highly flexible and durable. Further, it is chemically very stable. Oxidized bitumen is a very flexible compound that is not only chemically stable but also a very durable compound apart from being completely water resistant. Lastly, it has some very prominent technical advantages that makes it a very sought after compound in various applications.
- Water Resistant
- Chemical Stability
Compared to paving grade bitumen:
- Reduced temperature susceptibility
- Exhibits a more ‘solid’ nature at ambient temperatures
- High penetration index
Oxidized Bitumen Application
Blown grade bitumen shall be broken up into small pieces and heated slowly to the application temperature of 220 ºC to 230 ºC.
Various Standard Specifications Of Oxidized Bitumen